I once asked, what’s 3d registration/reconstruction/pose estimation is about – optimization or statistics? The more I think about it, the more I convinced it’s at least 80% statistics. Often specifically optimization tricks like Tikhonov regularization have statistical underpinning. Stability of optimization is robust statistics(Yes I know, I repeat it way too often). Cost function formulation is a formulation for error distribution and define convergence speed.
Now unrelated(almost) AR stuff:
I already mentioned on Twitter that version of markerless tracker for which I did a lot of work is part of Samsung AR SDK (SARI) for Android and Bada. It was was shown at AP2011(Presentaion and also include nice Bada code). AR SDK presentation is here.
Some videos form presentation – Edi Bear game demo with non-reference tracking at the end of the video and less trivial elements of SLAM tracking. Other application of SARI SDK – PBI (This one seems use earlier version).